java programs

Learn about how to check if String has all unique characters in java

In this post, we will see how to check if one String is rotation of another or not. For example: [crayon-6819e4ae71ce2662208688/] Approach: Lets say you need to check whether str1 and str2 is rotation of one another or not. Create a new String with str3= str1 + str1 Check if str3 contains str2 or not. […]

In this post, we will see how to check if two Strings are Anagrams in java. Anagrams mean if two Strings have the same characters but in a different order. For example: Angel and Angle are anagrams There are many ways to check if Strings are anagrams in java. Some of them are: Using String […]

In this post, we will see how to find duplicate Characters in a String. Approach: Create a HashMap and character of String will be inserted as key and its count as value. If Hashamap already contains char,increase its count by 1, else put char in HashMap If value of Char is more than 1, that means it […]

In this post, we will see how to find Greatest common divisor(GCD) and Least Common Multiple(LCM) in java. GCD is calculated using Euclidean algorithm and LCM is calculated using reduction by GCD Eucid algo for calculating GCD is: Lets say , there are two numbers , a and b so GCD of two numbers = […]

I have been posting java interview programs on various topics such as Binary tree, LinkedList , String, Number, ArrayList, HashMap etc. So I am consolidating list of java interview programs to create an index post. I will keep adding links to this post whenever I add any new program. These are frequently asked java programs […]

If you want to practice data structure and algorithm programs, you can go through 100+ java coding interview questions. Fibonacci series is numerical series in which next number is sum of previous two numbers. For example : 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55 etc. There are two ways to print Fibonacci […]

One of the interview question is “How will you find first non repeating character in String.” For example: If input string is “analogy”,  then program should return ‘n’ If input string is “easiest”, then program should return ‘a’ First approach: We will use [LinkedHashMap](https://java2blog.com/linkedhashmap-in-java-with-example/ “LinkedHashMap”) to find first non repeating character in String. Algorithm: Get […]

In this post, we will see java program to find all substrings of a String. For example: If input is “abb”  then output should be “a”, “b”,”b”, “ab”, “bb”, “abb” We will use String class’s subString method to find all subString Program: [crayon-6819e4ae72913120322190/] When you run above program, you will get following output: [crayon-6819e4ae72919957486274/] Above […]